fix(cockpit): production review pass — 22 fixes across 14 examples

[blove]

Summary

Production review of all 14 cockpit Angular examples for correctness, clarity, and learner-friendliness.

Critical fixes (2)

• planning — broken style="{{ expr }}" interpolation → [style.color]="expr"
• sandboxes — broken style="{{ expr }}" interpolation → [style.background]="expr"

Important fixes (10)

• interrupts — replaced internal "Tier 3" comments with learner-friendly explanations
• time-travel — added JSDoc explaining replay vs fork distinction
• deployment-runtime — currentThreadId converted to signal; hardcoded colors → CSS vars
• 6 deep-agents — all sidebars now always visible with empty-state text
• 4 deep-agents — replaced (msg as any).tool_calls with typed getToolCalls() API

Suggestions (5)

• Added file-level JSDoc to persistence, time-travel, durable-execution
• Made deployment-runtime properties protected readonly

Test plan

• nx run-many -t build --projects='cockpit-*-angular' — all 14 build
• nx test render && nx test chat — all pass